The Cessna 120-140 Association Forum

Several have installed the Odyssey battery, which one was used, and what was the justification used in the logbook entry? I assume identicality but thought I’d ask.
As a funny side, a proper AGM that fits in an early model Mazda Miata just about can’t be found anymore, but a Concorde RG-25 is a perfect fit if you change the terminals on the cars battery cables.
This os a Mazda battery beside of an RG-25XC. I ordered an Odyssey 925 and may put it in the Cessna and the Concorde in the car.

You have to use the SBS-J16 which is PMA approved for a lot of aircraft, although not for the 120/140. Use AC43.13-2a (not 2b) instructions for battery installations. 2a discusses spacers made of wood. That information was deleted from the most recent version. Write it up as a minor modification with a log book entry and done.

Thanks, but with it not being in the latest manual, is the info still valid?
There has been a lot removed

I did this over the winter. Replaced the battery and box. Used the odyssey paperwork and a previous 337 for reference. IA signed off as minor. Saved 8.5 lbs.

I did a bunch of other stuff at the same time and saved 18 lbs total. This is a painted plane with most of an interior, carpeting, child seat, 3200 TW, Clevelands, and full night lighting. Still only 950lbs, weight after all the changes. I could get it close to 900 if I wanted to strip the interior, child seat, new starter, remove original landing light, light TW, strip the paint, etc. but it flies great at 950 so just not worth the effort.

a64pilot wrote: ↑Fri Jun 04, 2021 10:53 am is the info still valid?

in my opinion, it has to be. Consider the ramifications if it were not.

Has there ever been an AD written on every aircraft ever equipped with a battery?

6643 wrote: ↑Tue Jun 08, 2021 8:19 pm

a64pilot wrote: ↑Fri Jun 04, 2021 10:53 am is the info still valid?

in my opinion, it has to be. Consider the ramifications if it were not.

Has there ever been an AD written on every aircraft ever equipped with a battery?

AC’s to start with are only Advisory, they are not approved data, the data may be used as a basis of approval.
But even FAR’s change all of the time, what that means is that they old ones are no longer applicable, it doesn’t mean that prior installations are no longer approved, it does however mean that that old data that has been superseded is no longer applicable.

You have to use the most current AC, regulation etc.

Using an old 337 to substantiate a minor alteration is illogical, the 337 substantiates it was a major modification, or there would be no 337.
It’s up to the mechanic to determine whether or not an alteration is minor or major, in my opinion installing a battery is minor, unfortunately in my opinion using a battery that’s not approved for the aircraft is not. I can’t use a Ni-Cad battery from a helicopter either even though it’s approved in aircraft and exceeds the requirements

I vaguely remember that maybe the TC for our 140 says something like 12V battery of 22 AH capacity, but doesn’t stipulate a model number?
If so then I think there is an effective argument that any 12V battery of at least 22AH will suffice, but I doubt you woud get much traction trying to use that logic to install a lithium battery, but a PMA battery I doubt you would get any flack in deciding it was a minor.
So much of aircraft maintenance is actually left up to the mechanic to make the decision, that’s good and bad.

If i were to install a battery as a minor, the logbook entry woud be installed battery model xxx as a minor alteration, weight and balance updated.
I would have no substantiation, no out of date pubs and certainly not a 337 from a previous install.

Oh, I put the Concorde back in the airplane and the Odyssey in the Miata

Deja vu! John C covered this in recent past probably before you came back aboard, Jody. I suggest you read the preamble to AC 43.13-!B & 2B. Yes, the data therein can be used for a "basis" for an approval but it can also be used as "approved" data if the 3 criteria are met that are listed therein. I have done just that on a 337 major alteration and coordinated the case with my FSDO contact and he said "send it in" and I asked for clarification, "do you mean send to you for review", and he said "no" send it direct to OKC!

I'm only addressing the approval issue - not the issue of updated info cancels previous published data.

Which part number Odyssey battery are most people installing in the Cessna 120/140 aircraft?

Odyssey Battery PC680 Extreme Powersport Battery or the PMA version P/N SBS-J16, you will have to add filler in the battery box to get a good fit also watch the battery date when you buy as these can sit on the shelf for years and look brand new. I have installed one of these batteries last winter and so far I have had 0 issues

I used the PMA'd battery and the fact that it was PMA'd as part of the justification. Using the 680 leaves you with very little basis for approval.

As far as AC43.13 goes, I don't recall whether the version I cited was approved data or just acceptable data and I don't have it handy here to check. Regardless, I think the fact that the information was omitted from the latest version rather than contradicted (prohibited) is an important distinction. I think if it were omitted with prejudice the latest version would say so. OTOH, if it's good enough for a '52 Bonanza then it' probably good enough for '46 140.

So, all of you that have a modern (Gil, Concord) 25 amp battery, what are you using to take up the extra space in the battery box?

If the next owner of my plane decides it's all bogus, there's nothing I did that can't be undone by simply replacing the battery.